Keloids are exuberant, tumor-like skin scars that occur unpredictably after injury to the skin in 10 to 20 % of dark skin races, i.e., people of African, Hispanic, and Asian descents. Currently there is no effective treatment to prevent or control the growth and expansion of keloid lesions, which are grievous to the psycho-social and overall health state of the affected individual. The goal of the proposal is to bridge the fundamental obstacles in keloid research by creating gene-targeted and fibrin matrix skin equivalent mouse models of keloid fibrosis, and assessing a RNA interference therapeutic approach. The plan is based on the long-term research effort of Dr. Tuan and the recent progress in keloid pathogenesis from the collaborative effort of Drs. Tuan and Benya (Multiple/Co-PIs). No animal models of keloid fibrosis currently exist that are applicable to routine testing or accurately reflect the human lesion. Moreover, for the development of knowledge-based therapies and their clinical application for keloids, candidate genes must be validated in vivo in animal models and shown to be responsive to targeted therapeutic treatments in such models. Three specific aims are proposed in this application to address the obstacles. Completion of the specific aims will provide a robust, gene-targeted, keloid-derived, skin equivalent animal model based on a three-dimensional fibrin gel mimic of provisional wound matrix. In addition, our target gene PAI-1, which is overexpressed by keloid fibroblasts and has been identified as causative in collagen accumulation in normal and keloid fibroblasts in vitro (published in Am J Pathol., Nov 2008), will have been validated in vivo as an important mediator of keloid fibrosis, while simultaneously demonstrating efficacy of an RNA interference therapeutic approach. Finally, the genetic manipulation of a normal human fibroblast cell line to mimic keloid fibrosis in the model will provide a substitute for keloid fibroblasts in efficacy evaluation and circumvent the limited supply of keloid tissues for routine testing. We also expect that these results and tools will enhance the rate of discovery research in keloid pathogenesis, furthermore, provide a platform, easily modified, for other investigators to validate target genes of interest in keloid fibrosis and test additional novel therapeutic approaches.